From owner-freebsd-geom@FreeBSD.ORG Thu Feb 10 00:43:07 2005 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E27A516A4CE for ; Thu, 10 Feb 2005 00:43:07 +0000 (GMT) Received: from hosea.tallye.com (joel.tallye.com [216.99.199.78]) by mx1.FreeBSD.org (Postfix) with ESMTP id BD2FC43D39 for ; Thu, 10 Feb 2005 00:43:06 +0000 (GMT) (envelope-from lorenl@alzatex.com) Received: from hosea.tallye.com (hosea.tallye.com [127.0.0.1]) by hosea.tallye.com (8.12.8/8.12.10) with ESMTP id j1A0h5Gf028119 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 9 Feb 2005 16:43:06 -0800 Received: (from sttng359@localhost) by hosea.tallye.com (8.12.8/8.12.10/Submit) id j1A0h52O028117 for freebsd-geom@freebsd.org; Wed, 9 Feb 2005 16:43:05 -0800 X-Authentication-Warning: hosea.tallye.com: sttng359 set sender to lorenl@alzatex.com using -f Date: Wed, 9 Feb 2005 16:43:05 -0800 From: "Loren M. Lang" To: freebsd-geom@freebsd.org Message-ID: <20050210004305.GA20199@alzatex.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i X-GPG-Key: ftp://ftp.tallye.com/pub/lorenl_pubkey.asc X-GPG-Fingerprint: B3B9 D669 69C9 09EC 1BCD 835A FAF3 7A46 E4A3 280C Subject: Understanding GEOM Ranking System X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Feb 2005 00:43:08 -0000 I'm slightly confused on the ranking system use in GEOM as described in the geom(4) manpage. The wording of the description seems a little confusing, but the way I understand it is that any geom instance which has no consumers attached to anything like a disk or acd geom has a rank of 1. Any geom that does have some of it's consumers attached to a provider has a rank of the highest ranked geom providing a service to this geom. For example, a ufs filesystem is running on a raid1 configuration between partition d on slice 1 on disk ad0 mirrored with slice 2 on disk ad1 (no disklabel on second disk). This makes two disk geoms for ad0 and ad1 both with rank 1. Each disk geom has a mbr geom on top of them with rank 2 (max(1)+1). The bsd geom on slice 1 of disk ad0 has rank 3 (max(2)+1). The mirror geom on top of the bsd geom and the mbr geom on disk ad1 has a rank of 4 since max(2, 3)+1 = 4. Then a dev geom on top of the mirror geom has a rank of 5 (max(4)+1). That dev geom is what is mounted as a filesystem on freebsd. Is this correct? dev(5) ---> mirror(4) ---> bsd(3) ---> mbr(2) ---> dev(1) ---> ad0 \-------------> mbr(2) ---> dev(1) ---> ad1 -- I sense much NT in you. NT leads to Bluescreen. Bluescreen leads to downtime. Downtime leads to suffering. NT is the path to the darkside. Powerful Unix is. Public Key: ftp://ftp.tallye.com/pub/lorenl_pubkey.asc Fingerprint: B3B9 D669 69C9 09EC 1BCD 835A FAF3 7A46 E4A3 280C